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* Create minmax.py * Update minmax.py * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci Co-authored-by: Christian Clauss <cclauss@me.com> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
70 lines
1.8 KiB
Python
70 lines
1.8 KiB
Python
"""
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Minimax helps to achieve maximum score in a game by checking all possible moves.
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"""
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from __future__ import annotations
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import math
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def minimax(
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depth: int, node_index: int, is_max: bool, scores: list[int], height: float
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) -> int:
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"""
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depth is current depth in game tree.
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node_index is index of current node in scores[].
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scores[] contains the leaves of game tree.
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height is maximum height of game tree.
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>>> scores = [90, 23, 6, 33, 21, 65, 123, 34423]
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>>> height = math.log(len(scores), 2)
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>>> minimax(0, 0, True, scores, height)
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65
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>>> minimax(-1, 0, True, scores, height)
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Traceback (most recent call last):
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...
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ValueError: Depth cannot be less than 0
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>>> minimax(0, 0, True, [], 2)
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Traceback (most recent call last):
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...
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ValueError: Scores cannot be empty
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>>> scores = [3, 5, 2, 9, 12, 5, 23, 23]
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>>> height = math.log(len(scores), 2)
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>>> minimax(0, 0, True, scores, height)
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12
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"""
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if depth < 0:
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raise ValueError("Depth cannot be less than 0")
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if not scores:
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raise ValueError("Scores cannot be empty")
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if depth == height:
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return scores[node_index]
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return (
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max(
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minimax(depth + 1, node_index * 2, False, scores, height),
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minimax(depth + 1, node_index * 2 + 1, False, scores, height),
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)
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if is_max
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else min(
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minimax(depth + 1, node_index * 2, True, scores, height),
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minimax(depth + 1, node_index * 2 + 1, True, scores, height),
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)
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)
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def main() -> None:
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scores = [90, 23, 6, 33, 21, 65, 123, 34423]
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height = math.log(len(scores), 2)
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print(f"Optimal value : {minimax(0, 0, True, scores, height)}")
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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main()
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